Wrap some function definitions with `HAVE_LIBCRYPTO` ifdefs to
match their usages in `torture_run_tests`.
Fixes this warning I observe when building locally:
torture_pki_ecdsa.c:341:13: warning:
‘torture_pki_ecdsa_write_privkey’ defined but not used
[-Wunused-function]
Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>